FR2835663A1 - DEVICE AND METHOD FOR REGULATING THE POWER PROVIDED BY A GENERATOR BY MODIFYING ITS PERFORMANCE - Google Patents

Abstract

Device and method for regulating the power supplied by a generator (1), in particular to an on-board electrical network of a motor vehicle, so as not to suddenly stress the motor driving the generator when a power source is plugged in or cut. electrical consumers (3), the invention provides means (4) making it possible to abruptly modify the efficiency of the generator (1) in reaction to the connection or cut-off of a consumer (3).

Description

104276 / INGINI / BD F: \ Salle \ F1 04276 \ PREM DEP \ TEXrE \ 104276Texte_déposé.doc

  The present invention relates to a device for regulating the power supplied by a generator, in particular to an electrical network.

  stick on board a motor vehicle.

  The invention also relates to a method for setting

s _work of such a device.

  PRIOR ART The electrical networks on board tomobile vehicles are usually powered by a battery and by a generator (alternator). An on-board network characteristic of a motor vehicle is shown schematically in FIG. 1. This on-board network comprises a generator 1, a battery, several consumers represented here overall by the consumer 3 as well as a regulator equipped with the generator . When a new consumer 3 is connected, the regulator 5 increases the power supplied by the generator 1 by a signal dF (regulation signal by which the excitation of the generator 1 is determined). The braking torque acting on the vehicle engine thus increases. However precisely at low speeds, especially at idle, this can cause a decrease in the speed of rotation up to

o stalling of the engine.

  To avoid such collapses in the engine speed, it is known to regulate the power supplied by the generator by a so-called load response function. Under these conditions, the excitation current and thus the power supplied by the generator is first abruptly reduced by the regulator and the supply to the consumer who has just been newly connected is then first provided by the bat terie 2 (the battery acts as a buffer). Then the excitation is increased along a ramp-shaped curve (that is to say with a fairly long time constant) to raise the output power of the generator 1 to the required level. This prevents the braking effect exerted by the generator on the engine from increasing too strongly. On the other hand, due to the low power supplied by the generator, in particular in the case of an insufficiently charged battery, there will be a collapse of the voltage.

on-board electrical network.

  3 s The build-up of high electrical consumers owes to relieve the generator 1 and thus to positive jumps of the torque at the generator 1. I1 again results in an increase in the rotation speed of the motor c ' i.e. irregular engine operation

  internal combustion. In addition, the generator output voltage increases

then lie.

  OBJECT OF THE INVENTION The object of the present invention is to avoid the influence of the generator on the motor while guaranteeing the stability of the voltage of the

on-board network.

  Description and advantages of the invention For this purpose the invention relates to a device of the type described above, characterized by means making it possible to suddenly modify

  o the efficiency () of the generator in reaction to the connection or the

pure from a consumer.

  The invention also relates to a method characterized in that the efficiency (rl) of the generator is suddenly modified during the

  connection or disconnection of a consumer.

  Preferably the means are made so as to regulate the efficiency () taking into account the power applied to the generator

  (signal dF) or engine speed (n).

  In addition, the means are in contact with a consumer manager (NIM) and with a detection of the state of the battery and

  o are able to regulate the yield () taking into account the state ac-

tuel of the battery.

  By increasing the efficiency when connecting another electrical consumer, the demand for power can be covered

  additional thus caused without immediate modification of the couple.

  Conversely, when switching off a consumer, the yield is reduced

  dement so that the generator will provide less output power

  dre without sudden change in torque.

  As a means of modifying the efficiency, it is possible, for example, to provide a control such as an impulse rectifier which is able to influence the efficiency of the generator, in particular

  turning the phase between the generator current and the voltage.

  Thus according to the method according to the invention, the output is suddenly increased () when a consumer is connected and the output () is suddenly lowered when a con is cut.

adder.

  We can regulate the yield for example according to the

  current generator load or engine speed.

  According to a first embodiment of the invention, for a low generator load the efficiency is set to a low level and for a high generator load it is set to a high level. Finally, the connection of another consumer when the generator is lightly stressed is much more likely than a higher load. If the load applied to the generator is for example too low, a yield reserve is kept to allow positive load jumps to be absorbed, that is to say the connection of consumers. On the other hand, for a high load applied to the generator, you can choose to set a higher efficiency because there will be predictably more jumps.

negative charge.

  In addition to this, the generator output is preferably kept at a low level at low engine speed, and at a high level for high engine speed, in order to have a sufficiently high yield reserve at low engine speeds. engine, and not to create too much lost power at high revs for which the engine anyway runs much more

stable.

  However for a low load applied to the generator o or a low speed, these measures lead to too much lost power

  important because due to the low efficiency, the generator does not provide

  only reactive power.

  Under these conditions it is advantageous that the regulation of the yield cooperates with a management of consumers delaying the connection of a consumer until the torque of the generator is again raised to a predetermined level. The expression "consumer management" in this context means an order which ensures the

  connection and disconnection of consumers taking account of con-

  preset editions (battery status, generator power), that is

  say allowing in particular to delay the connection over time.

  The use of consumer management makes it possible to adapt the return

  generator before any future switching occurs

  (connection or disconnection of a consumer).

  The regulation of the generator output by a 3s management of consumers is essentially carried out as follows: In a first step, the connection of the

  consumer; in a second step, the yield of the ge

  generator along a ramp (with a large time constant).

  At the same time the decrease in the power of the genera-

  In principle caused by a change in yield is compensated in principle by other means such as, for example, a stronger excitation of the generator and finally the consumer is connected with an aug

  sudden mention of the yield (short time constant).

  According to another embodiment of the invention, it is possible to

  regulate the yield taking into account a detection of the state of the bat-

  crocheted. The adjustment of the generator output can thus be granted following

  the current state of the battery (state of charge or capacity

o power).

  Drawings The present invention will be described below in more detail with the aid of the attached drawings in which: - Figure 1 is a schematic view of an on-board network of a motor vehicle; - Figure 2 shows the curve representing different magnitudes of the generator when connecting a consumer; - Figure 3 shows the evolution of different magnitudes of the generator when switching off a consumer; - Figure 4 shows the evolution of different sizes of the generator when connecting a consumer in cooperation with a ges

consumer.

  Description of embodiments

  FIG. 1 shows an on-board network of a mobile automobile vehicle comprising a generator 1, a battery 2 and several consumers capable of being connected. These consumers are represented schematically by the load 3. To regulate the voltage or

  the generator power is provided with a regulator 5.

  When an electrical consumer is connected, the electrical output power P2 of the generator changes AP. To generate this additional power AP, it is necessary to provide additional engine power P2 ′ by the motor. So we have the relationships

P2 = P1.11 1

P2 '= P2 + AP

P2 = P1.112

  In these relationships, P2 'represents the power of the generator after the connection of a consumer; 1 represents a lower yield and rl2 a higher yield. As mathematical relationships show, by increasing the yield we cover the

  s request for additional electrical power without variation in torque.

  FIG. 1 also shows an installation 4 for regulating the efficiency of the generator. This installation receives a signal df, the engine speed n or equivalent quantities from which the quantities thus evoked can be deduced. The installation 4 can furthermore be connected to a management of consumers VM and regulate the generator as a function of a control signal coming from the management of consumers. The generator output is adjusted, for example, in turn

  nant the phase between the intensity of the generator current and the voltage.

  FIG. 2 shows the evolution over time of different s magnitudes of the generator when a consumer is connected (positive charge jump). In the example shown, the consumer is connected at time t0. At the same time, the yield is suddenly increased from a low level q 1 to a high level 2 (branch a). The generator output power thus suddenly increases by the AP value, going from a power P2 to a new output power P2 'without

  apply additional braking torque to the engine.

  At time tl the new output power P2 'is reached and the efficiency rl2 can then be reduced along a ramp curve (branch b), that is to say with a time constant greater than the s branch a to return to the lower value q 1. At the same time, the torque required for the higher output power P2 'will be adjusted by

a ramp (stronger excitement).

  As the curve shows, the output voltage of the gene

  rator is kept constant during this operation.

  n / a Figure 3 shows the evolution of the main quantities of the generator for a negative charge jump. By switching off an electrical consumer, the electrical output power P2 of the generator is changed by the value AP. This results in a reduction in the torque applied to the motor. If now, when switching off the consumer (instant tO) we reduce the yield q2, abruptly (branch a) and if we then return in the form of a ramp (branch b) to the initial value 2, we can control desired way the gradient of the torque evolution (see the area

  circled). In addition, the output voltage Ua is kept constant.

  By cutting an electrical consumer, we have the following relationships: P2 = P1 e2 s P2 '= P2 + AP

P2 '= P1 TO 1

  To regulate the output power P of the generator for a positive charge jump as shown in FIG. 2, however, has drawbacks. To have sufficient possibilities for the sudden increase in the efficiency (branch a), it is necessary that in the more critical operating modes, in particular when the engine is running at idle or when the generator is very lightly loaded, that the efficiency is maintained at a sufficiently low level (for example s between 50 and 60% of the maximum value). For such a low efficiency, however, the generator provides a relatively high lost power which results in an increase in fuel consumption. According to another development of the invention represented in FIG. 4, means 4 are proposed for this to modify the yield by cooperating with the management of consumers VM allowing to delay the connection of consumers 3. This solution has the advantage of allowing the torque to be adjusted after a connection request at the instant te, first of all following a ramp shape to reach a higher level M2 while lowering the efficiency following a ramp-shaped curve up to a lower level 1. The output power P of the generator thus remains practically unchanged at the value P1. After this short time delay, the consumer 3 is finally connected at the instant t0 and at the same time the yield is raised, abruptly (branch a) to the value 2. This also suddenly increases the power supplied by the generator of the value AP without influence the couple. In this way we can also maintain the yield

  engine idling always at optimum, high level.

3s

Claims (6)

RESELL I CATI O N S   1) Device for regulating the power supplied by a generator (1), in particular to an on-board electrical network of a motor vehicle, characterized by means (4) making it possible to suddenly modify the efficiency () of the   generator (1) in response to the plugging in or out of a consumer mateur (3).   2) Device according to claim 1, o characterized in that the means (4) are made so as to regulate the efficiency (rl) taking into account the power applied to the generator (signal df) or the speed motor (n).   3) Device according to claim 1, characterized in that the means (4) are in relation with a consumer manager VM). 4) Device according to claim 1, characterized in that the means (4) are related to a detection of the state of the battery and are able to regulate the efficiency () taking into account the ac state tuel of the battery.    ) Method for regulating the power supplied by a generator (1), in particular to an on-board electrical network of a motor vehicle, characterized in that the efficiency () of the generator is suddenly modified during the branch   of a consumer (3).   6) Method according to claim 5, characterized in that the yield () is suddenly increased when connecting a consumer (3).   7) Method according to claim 5, characterized in that   the output () is abruptly lowered when a con- summator (3).   8) Method according to claim 5, characterized in that the efficiency is maintained (rl) at a low level for a low load (dfl applied to the generator, and the efficiency is maintained at a high level   for a high load applied to the generator.   o 9) Method according to claim 5, characterized in that at low speed (n) the efficiency () is maintained at a low level and at re   gime (n) high the yield is maintained at a high level.   s 10) Method according to claim 5, characterized in that   we control the vafiation of the yield () by a consumption management mateurs (VM).   o 11) Method according to claim 5, characterized in that - the connection of a consumer (3) is delayed by a consumer management (VM); - the output is lowered () in the form of a ramp during the tempering time and at the same time the torque of the generator (1) is increased to act against the variation in power due to the reduction in efficiency (rl)); and - the consumer is finally connected (3) while increasing gross only the yield ().